Déjà vu may be an eerie shadow of the mind at work, 

and a window into the mind’s evolutionary past. 

Most of the time, our cognitive processing takes place smoothly 

and effortlessly – we just process the world around us 

and retrieve relevant information rapidly, 

without introspective access to how that occurs. It just does. 

Déjà vu occurs when there is a hiccup in the system, 

and we notice the pull on our attention; it grabs hold of our focus,

allowing us to catch a quick glimpse of our memory’s operation

occurring in slow motion. What would ordinarily take place quickly

beneath the surface – the unfolding process of familiarity-detection

followed by inward-directed attention and retrieval search effort

leading to retrieval of relevant information – suddenly has a light

shining on the spot where the halt occurred, where the retrieval piece

was not successful, and we find ourselves in a heightened state 

of searching our memory, trying to find out why the situation feels so

familiar. But rather than being an odd quirk of memory, this 

cognitive mechanism could be forcing us to retrieve the very memories

we need to survive – and could be evolution’s way of forcing the mind

inward, when it needs that insight most.

Ann Cleary